Process of roasting and disintegrating gold



1 precious metals, more especially those having ,20 I possible, and all is designed to improve upon UNITED STATES {PATENT OFFICE DAVID WALTON BIRMINGHAM, orcLIF'roN, NEW YORK.

PROCESS OF ROASTING AND DISIN TEGRATING GOLD, SILVER, AND COPPER ORES.

. SPECIFICATION forming part of Letters Patent No. 296,116 dated April 1, 1884.

Application filed November 6, 1883. a (No specimens To aZZ whom it may concern:

Be it known that I, DAVID WALTON BIR- MINGH M, a citizen of the United States, residing at Glifton, in the county of Richmond and State of New York, have invented new and useful Improvements in Process of Roasting and Disintegrating Gold, Silver, and Copper Ores, of which the following is a specification.

My invention relates to certain improvements in the treatment of ores containing fluxing or slagging, and prepares the ores for av more perfect and effectual amalgamation,

whereby I obtain a higher percentage of value from a given quantity of ore than is otherwise the invention set forth in my Reissued Letters Patent No. 10,400, dated November 6,1883.

To this endmy invention consists in mechanically combining the broken ores which have been crushed and reduced to requisite fineness with abulk of broken or pulverized charcoal or other carbonaceous substance, and any salt of. lime, preferablythe hydrate, or any 1 s calcareous, aluminous, or magnesian material, and in combinationwith one or more of the following substances: common salt, saltpeter,

i or anyform of nitrates, manganese, sulphate I of iron, sulphate of copper, and roasting the said ores so combined in a reverberatory or other furnace suitable for the purpose, and subsequently subjecting the charge, while heated, to a bath of water, but preferably of a solution of common salt, cyanide of potassium, and sulphate of copper, or to any suitable bath of an acidulated, saline, or alkaline solution, according to the refractory bases of the ore, and which bath may be applied to the in the proportion, say, of about one bushel (more or less) of each to one ton of the ore. While I may use any form of lime or its equivalent for this purpose, the hydrate is to be preferred, and although the proportions of the lime to the charcoal nrentioned may be taken as the standard, it should be noted that this is subject to variation according to the fusible character of the ore under-treatment, the fu sion of which it is desired to prevent, the salt or equivalents being used in quantities as the nature of the rebellious ores require, and are either combined with the ores at the commencement of the roast or applied and intermixed during the difierent stages thereof.

The art or principle of working is set forth coal or other carbonaceous material and lime through a suitable aperture into the upper end, say, of a reverberatory furnace having,

preferably, an inclined' hearth, or in any suitable furnace, and then subjected to a gradual roast by impinging upon the mass the heat or flame derived from a fire made from wood or any suitable material, the important feature being to gradually raise the temperature of the ore as high as possible without and their character may suggest by approaching the same nearer to the fire located at the other end of the furnace, and is accomplished ordinarily in reverberatory furnaces by rakes or other tools made and used for that purpose. At each periodical movement down or removal of said ores to a nearer approach to said fire after a discharge of similar quantity of roasted ores another charge of similar bulk is admitted, as before, and this plan is pursued until the gases, fumes, and refractory bases are eliminated, when, by an exit in the hearth constructed for the purpose, they are discharged at a red, White, or intermediate heat,

as the case may require, into a bath, as herein more fully set forth. The presence of lime,

The salt or equivalents,while combined with matting or slagging.

lime and charcoal in the roast, assists materially as a desulphurizer, attacking the bases with energy and by chemicaltransformation throwing them into a harmless condition, shortening the time required for roasting, while the lime and charcoal act as absorbents and prevent It should also be noted that while I may use the combination of. lime and charcoal, as specified, I am not to be restricted to their combined use with all classes of ores in the manner referred to 5 but I may defer using either of these materials when they or their equivalents are found in natural combination with the ores themselves-that is to say, for instance, when ores'contain sufficient lime in themselves I may simply use the charcoal therewith, with salt or equivalent, and when ores require less heat I may use the lime alone with the ores, with salt or equivalent.

Now, when I have prepared the ores by a ,thoroughroast in the manner before described after their desulphurization, and the ores at proper temperature of heat, I at once discharge them into a water bath, or a bath composed, preferably, of an aqueous solution of chloride of sodium, cyanide of potassium, and

sulphate of copper prepared in the following manner: Within a vat or car made of suitable dimensions and used for receiving the discharge, I form a solution of common salt,

sulphate of copper, and cyanide of potassium with water, the proportions being about one pound (more or less) of. each of the substances named, to a'sufficient volume of water to cover the bulk of ore roasted at a single operation, salt being added to the point of saturation. WVhile'I may use this combination pref- 5o erably as a whole, I may also use them separately or in following quantities, to wit: say one pound of the cyanide of potassium to a sufficient quantity of water to cover the ore, salt being added to saturation, or in accord- 5 ance with the quality and refractory condition of the ore to be treated. I may use any saline, alkaline, or acidulated bath, singly or in combination, as while some ores are successfully treated in one solution other ores may require and be more advantageously treated in a solution composed of different ingredients. The action of the roast, in combination with this bath, upon the heated ores effects their disintegration, leaving them in a friable condition, in which they are readily crumbled or pulverized, thereby effecting a more complete separation of the bases, setting free the precious metals, and leaving the ores in condition for amalgamation. aside from its advantages, secures much economy as compared with other methods.

WVhat I claim is The process herein described of preparing refractory ores for amalgamation, consisting in combining therewith lime, carbon, and common salt, or equivalents, roasting the mixture, and then subjecting the same to a suitable bath, substantially as described.

In testimony whereof I have hereunto set my handjn the presence of two subscribing witnesses. DAVID WALTON BIRMINGHAM. VYitnesses:

GEO. G. HULL, MARTIN SCHULTZ.

This process, 70 

